A window regulator (a vehicular opening-closing body driving device) has a basic configuration that includes a guide rail extending in a longitudinal direction, a slider base that is supported to this guide rail so as to be freely movable up and down and a window glass (a vehicular opening-closing body) is supported to the slider base, a drive wire to move this slider base up and down and drive along the guide rail, a drive drum around which this drive wire is wound, a drum housing that rotatably houses and supports this drive drum, and a motor unit that is supported to this drum housing and rotatably drives the drive drum.
Manufacturing this type of window regulator requires a process for winding the drive wire around a spiral groove (a drive-wire winding groove) formed on a peripheral surface of the drive drum. This process may be executed before the drive drum is housed and supported to the drum housing, or may be executed after the drive drum is housed and supported to the drum housing.
When the drive wire is wound around the spiral groove in a normal manner, the drive wire is wound along the spiral groove without protruding from the spiral groove and with a tension applied to an extent sufficient for use state. In contrast, when the drive wire is wound around the spiral groove in an abnormal manner, the drive wire is wound not along the spiral groove but protrudes from the spiral groove (for example, a groove-skip winding), or wound in a loosened state without a tension applied to an extent sufficient for use state. In the case of the abnormal winding, an abnormal noise or an operation failure occurs in operating the window regulator.    Patent Document 1: JP-A-2011-12469